Extensions · Poole, Dorset

House extensions in Poole, designed and built by one team.

An extension needs a survey, drawings, approvals, structural calculations and the building work. We do all of it, so you only deal with us.

  • ★ 5.0 on Google (15 reviews)
  • Checkatrade 10/10 (20 reviews)
  • We reply the same working day.
A finished single-storey extension with a rear patio

What we cover

Types of extension

There are three common types of extension. We will tell you which type fits your house and budget once we have seen it.

01

Single-storey extension

Built at the back or side of the house, or both. It adds space on the ground floor, often a bigger kitchen or living room.

02

Two-storey extension

Adds a room upstairs as well as space downstairs. The foundations have to be strong enough for two floors.

03

Internal reconfiguration

No new building outside. We move or take out walls inside the house to change the layout.

The survey includes accurate measurements of your house and at least two layout options.

Why homeowners choose us

We combine design and construction experience, so the early layout discussion considers how a home could be altered as well as how it could look. Detailed scope, pricing and programme are agreed separately for each project.

Free

Free project review

Tell us what you want to do. We call you back the same working day to tell you what your project needs and whether it is worth doing. There is no cost and no obligation.

Clearer scope before work begins

We use the available drawings and project information to discuss the proposed work before a quote and contract are agreed.

One firm and one contract

You don't have to find and manage separate designers, engineers and builders.

You can stop after any step

The drawings are yours to use with any builder.

How a building project works

Every extension, knock-through or loft conversion has four stages. We do all four.

  1. 01

    Drawings

    We measure your house and draw it as it is now. Then we draw the new layout.

  2. 02

    Approvals

    We apply for planning permission if you need it, and prepare the Building Regulations drawings. Building Control is an independent inspector. They check the work and sign it off.

  3. 03

    Engineering

    A structural engineer works out the size of any steel beams and foundations before building starts.

  4. 04

    Building work

    We do the building work and finish the rooms.

For an extension, the regulations stage usually means planning, Building Control, or both. We check which applies before any drawings are started.

Photos from our jobs

These are our sites, photographed as the work happened.

Foundations going in
Foundations going in
Steel beam going in
Steel beam going in
Roof and blockwork
Roof and blockwork
Glazing going in
Glazing going in
A finished single-storey extension
A finished single-storey extension
A finished living space
A finished living space

See more of our work

How it works

There are five steps. You can stop after any of them.

You can stop after any step. The drawings are yours, and you can use them with another builder.

We build in Poole, Bournemouth, Christchurch and about 20 miles around them. For homes further away, our remote layout service works anywhere in the UK, and we can price the work, prepare tender documents and vet local builders.

  1. Step 1

    Free project review

    Send us a few details or call. We look at what you want to do and tell you what it will need and whether it is worth taking further.

    Free

  2. Step 2

    Layout Ideas Pack

    We draw your home as it is now and up to three ways it could work, then fine-tune your favourite with you on a video call. Done remotely from your Rightmove link, floor plan or sketch, or in person with a measured site survey and a 3D point cloud scan.

    Remote or in person

  3. Step 3

    Cost estimate

    Once you have a layout you like, we can explain the further work needed and quote any separately agreed service.

    Quoted separately

  4. Step 4

    Drawings, approvals and engineering

    Full drawings, structural calculations, and the planning and Building Regulations applications. The house is measured at this stage if it hasn't been already.

    Priced after the estimate

  5. Step 5

    The build

    Near Poole, we can prepare a quote and contract using the information available for the agreed scope. Changes, site conditions and client decisions can affect scope, cost or programme. Further away, we can prepare tender information and support the selection of local builders.

    Quoted for the agreed scope

What our customers say

  • ★ 5.0 on Google (15 reviews)
  • Checkatrade 10/10 (20 reviews)
  • We reply the same working day.
“…they can do everything from start to finish for you.”
Sandra W. · Google review · April 2026
“…carried out layout drawings for a very reasonable amount. Josh also gave us a budget price to carry out the works.”
Lee B. · Google review · August 2024
“I couldn't recommend Josh enough! He has been absolutely fantastic, nothing was too much trouble, he was happy to bounce lots of ideas back and forth until we were happy. He is polite, friendly and professional in every aspect. I would definitely be using his services again in the future when needed.”
Kirsty H. · Google review · January 2024
“Josh got the plans for our extension completed and submitted very quickly. We had a number of amendments and obstacles to overcome but nothing was too much trouble for him. A very professional and efficient service.”
Lester M. · Google review · February 2021
Josh Carrivick, founder of PlanBuild

How we help

You want more space or a better layout, but you don't know where to start, what it will cost, or who to trust with it.

We tell you what your project needs

At the free review we tell you whether you need planning permission, Building Regulations approval or a structural engineer, and what that involves.

You see your options before you commit

The Layout Ideas Pack gives you up to three layout options for your house, so you can decide which direction is worth developing.

You can discuss the next stage clearly

Once a direction is chosen, we can explain the surveys, approvals, technical work or construction services that may be needed.

You deal with one firm

We do the drawings, the approvals, the engineering and the building work. You don't have to find, manage and chase separate firms.

Questions

Do I need planning permission for a house extension in Dorset?

Many single-storey rear extensions fall under Permitted Development rights and don't need a planning application. We check your project and tell you whether you need a full Householder Planning Application or a Certificate of Lawfulness.

How much does it cost to get extension plans drawn up?

Start with the Free Project Review, free. If it makes sense to go ahead, the next step is the Layout Ideas Pack, done remotely or in person.

How long does it take to receive my extension plans?

We reply the same working day to agree a time. Drawing time after that depends on whether it is a simple layout change or full planning and Building Control drawings.

What is a Certificate of Lawfulness?

A Certificate of Lawfulness confirms that your proposed extension falls within Permitted Development rights and doesn't need full planning permission. It is legal proof that your build is lawful, which mortgage lenders and future buyers ask for. We can handle the application.

Tell us what you want to change

Send a few details and we will call you back the same working day to tell you what your project needs. There is no cost and no obligation.

We build in Poole, Bournemouth, Christchurch and about 20 miles around them.

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